a). At first, please check User Name and Password on the phone and make sure that it is the same as User Name and Password that is used from computer side in attempt to connect SymSMB shared folder. To make sure that everything is correct, please re-type password in SymSMB. Consider to do the same with password on computer if you have any doubt. Pay attention to the Capital letters (Caps Lock), possible language switch, spaces at the beginning, end and between letters in the password string.
Please check the User Name on phone and computer as well.
b). Check if Permissions to access Shared Folder on the phone are correctly configured for the same User Account that is used from computer side in attempt to connect SymSMB shared folder.
c). Check if some antivirus/firewall software on the phone, for an example "F-Secure" (pre-installed on some Nokia's phones), could create this situation. Disable/uninstall or reconfigure this software and see if there is a difference.
d). Check if some antivirus/firewall software on the computer, could create this situation. Disable/uninstall or reconfigure ...
e). Check if router could block or redirect some information. Disable or reconfigure ...
f). If you are using connection over Internet, check if Internet provider could block some information. Contact or change Internet provider if quality unrestricted access is important for you.